A polycarbonate/polyester alloy has good heat and chemical resistance characteristics and has been often used especially for automotive parts.
In recent years more thin-walled parts have been required from the viewpoint of weight saving, which in turn has led to the request for the improvement of fluidity of materials.
In addition to the characteristics above, the polycarbonate/polylactic acid alloy which is a polycarbonate/polyester alloy is effective for the high fluidization of polycarbonate due to the high fluidity of polylactic acid.
Since it is thought that polylactic acid produces less toxic gases when it is burned with polycarbonate in alloy due to chemical construction thereof, it is also expected that the polycarbonate alloy is excellent for environment.
Although the conventional polycarbonate/polyester alloys have good heat and chemical resistance characteristics, they have poor fluidities. In order to obtain a high fluidity of the polycarbonate, an alloy with styrene resin or a plasticizer is generally added (Patent Document 1).
Although polycarbonate/polylactic acid alloys with a luster of pearl, excellent fluidity, and good thermal and mechanical characteristics are known, further improvement of fluidity is necessary for molded articles with complicated shapes such as those of office automation equipment (Patent Document 2).
Polycarbonate resins have a self-extinguishing characteristic, however, there are fields which require a more severe flame retardancy in the field of electric and electronic equipment including office automation equipment, information and communication equipment and electric home appliances and such a characteristic has been improved by adding various flame retardants.
As a technique of improving the flame retardancy of polycarbonate resins, a halogen flame retardant such as halogenated bisphenol-A and halogenated polycarbonate oligomer has been used in combination with a flame retardant assistant such as antimony oxide from the viewpoint of flame retardant efficiency.
In recent years, however, the market demands flame retarding methods using flame retardants which do not contain halogens from the viewpoint of safety and effects on the environment after disposal and incineration.
Organic phosphorus flame retardants, especially polycarbonate resin compositions containing organophosphate ester compounds, have the action of plasticizer as well as excellent flame retardancy as such non-halogen flame retardants and many methods for them were proposed.
Additionally, a flame retardant resin composition in which a polycarbonate-polyorganosiloxane copolymer is used as a polycarbonate resin and which is made of a polycarbonate resin composition containing polytetrafluoroethylene with a fibril-forming ability is also know (Patent Document 3).
This composition shows excellent flame retardancy when the content of polyorganosiloxane is limited to a specific low range.
Although methods that use organic alkali metal salt, organic alkaline earth metal salt, or polyorganosiloxane to improve flame retardancy without compromising transparency are also known (Patent Document 4), all the methods require further improvement of fluidity.
The use of styrene resins or aromatic polyester resins to improve the fluidity of polycarbonate resin is known (Patent Document 5), but there is no description of a high-flow flame retardant polycarbonate resin using a fatty acid polyester or even polycarbonate-polyorganosiloxane copolymer.
Patent Document 1: JP-B-H07(1995)-68445
Patent Document 2: JP-A-H07(1995)-109413
Patent Document 3: JP-A-H08(1996)-81620
Patent Document 4: JP-A-H08(1996)-176425
Patent Document 5: J-A-2003-147188